[PATCH AUTOSEL 6.14 507/642] net: fec: Refactor MAC reset to function

Sasha Levin
2025-05-05T22:35:06Z

From: Csókás, Bence <csokas.bence@prolan.hu>

[ Upstream commit 67800d296191d0a9bde0a7776f99ca1ddfa0fc26 ]

The core is reset both in `fec_restart()` (called on link-up) and
`fec_stop()` (going to sleep, driver remove etc.). These two functions
had their separate implementations, which was at first only a register
write and a `udelay()` (and the accompanying block comment). However,
since then we got soft-reset (MAC disable) and Wake-on-LAN support, which
meant that these implementations diverged, often causing bugs.

For instance, as of now, `fec_stop()` does not check for
`FEC_QUIRK_NO_HARD_RESET`, meaning the MII/RMII mode is cleared on eg.
a PM power-down event; and `fec_restart()` missed the refactor renaming
the "magic" constant `1` to `FEC_ECR_RESET`.

To harmonize current implementations, and eliminate this source of
potential future bugs, refactor implementation to a common function.

Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Csókás, Bence <csokas.bence@prolan.hu>
Link: https://patch.msgid.link/20250207121255.161146-2-csokas.bence@prolan.hu
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/freescale/fec_main.c | 52 +++++++++++------------
1 file changed, 25 insertions(+), 27 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index f7c4ce8e9a265..a86cfebedaa8b 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1093,6 +1093,29 @@ static void fec_enet_enable_ring(struct net_device *ndev)
}
}

+/* Whack a reset. We should wait for this.
+ * For i.MX6SX SOC, enet use AXI bus, we use disable MAC
+ * instead of reset MAC itself.
+ */
+static void fec_ctrl_reset(struct fec_enet_private *fep, bool allow_wol)
+{
+ u32 val;
+
+ if (!allow_wol || !(fep->wol_flag & FEC_WOL_FLAG_SLEEP_ON)) {
+ if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES ||
+ ((fep->quirks & FEC_QUIRK_NO_HARD_RESET) && fep->link)) {
+ writel(0, fep->hwp + FEC_ECNTRL);
+ } else {
+ writel(FEC_ECR_RESET, fep->hwp + FEC_ECNTRL);
+ udelay(10);
+ }
+ } else {
+ val = readl(fep->hwp + FEC_ECNTRL);
+ val |= (FEC_ECR_MAGICEN | FEC_ECR_SLEEP);
+ writel(val, fep->hwp + FEC_ECNTRL);
+ }
+}
+
/*
* This function is called to start or restart the FEC during a link
* change, transmit timeout, or to reconfigure the FEC. The network
@@ -1109,17 +1132,7 @@ fec_restart(struct net_device *ndev)
if (fep->bufdesc_ex)
fec_ptp_save_state(fep);

- /* Whack a reset. We should wait for this.
- * For i.MX6SX SOC, enet use AXI bus, we use disable MAC
- * instead of reset MAC itself.
- */
- if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES ||
- ((fep->quirks & FEC_QUIRK_NO_HARD_RESET) && fep->link)) {
- writel(0, fep->hwp + FEC_ECNTRL);
- } else {
- writel(1, fep->hwp + FEC_ECNTRL);
- udelay(10);
- }
+ fec_ctrl_reset(fep, false);

/*
* enet-mac reset will reset mac address registers too,
@@ -1373,22 +1386,7 @@ fec_stop(struct net_device *ndev)
if (fep->bufdesc_ex)
fec_ptp_save_state(fep);

- /* Whack a reset. We should wait for this.
- * For i.MX6SX SOC, enet use AXI bus, we use disable MAC
- * instead of reset MAC itself.
- */
- if (!(fep->wol_flag & FEC_WOL_FLAG_SLEEP_ON)) {
- if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES) {
- writel(0, fep->hwp + FEC_ECNTRL);
- } else {
- writel(FEC_ECR_RESET, fep->hwp + FEC_ECNTRL);
- udelay(10);
- }
- } else {
- val = readl(fep->hwp + FEC_ECNTRL);
- val |= (FEC_ECR_MAGICEN | FEC_ECR_SLEEP);
- writel(val, fep->hwp + FEC_ECNTRL);
- }
+ fec_ctrl_reset(fep, true);
writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);
writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);

--
2.39.5